feat: S11 - explicit VCU stop command on 0x212 byte 3 (replaces udclim hack)

The -S10 udclim=200V mechanism was a hack — VCU lowered udclim below
pack to fire CheckVoltage() udc>udclim and force STOP. It didn't work
reliably because once VCU opens HV contactors, the OBC per-module
voltage probes (c1udc/c2udc/c3udc) collapse below 200V and udc =
MAX(c1,c2,c3) never accumulates 10 ticks above udclim. Bench symptom:
VCU reaches CHARGE_COMPLETE, opens contactors, but teslacharger stays
in EVSEACTIVATE, OBC modules keep drawing ~0.5kW AC, water pumps run,
CP signal stays charging, EVSE doesn't shut down.

S11 adds an explicit vcustop byte on 0x212 byte 3 — VCU sets it to 1
when it wants charging stopped. ChargerStateMachine checks vcustop
FIRST in the EVSEACTIVATE case and transitions to STOP immediately.
Mirrors how the Dilong OBC obeys OBC_ControlCMD = Stopped.

Wire format (additive, no breaking change to S10):
  Byte 0:    vcuchglim_pct  (existing)
  Bytes 1-2: udclim_V       (existing, DEPRECATED — VCU sends 398V no-op)
  Byte 3:    vcustop        (NEW, 0=normal / 1=force stop)
  Bytes 4-7: reserved

Defensive: Param::Change(udclim) now clamps received <50V values to the
398V flash default. Protects against a pre-PR47 VCU sending all-zeros
in bytes 1-2 (which would otherwise make CheckVoltage() fire constantly
and brick charging).

After this VCU also flashed: the WPUMP issue resolves naturally because
VCU_IsCharging() reads OIOBC.State < ACTIVATE once teslacharger goes
to STOP. The VCU/teslacharger ownership becomes symmetric with the
Dilong path — VCU is authoritative for "should we charge."

Pool: 43 → 44 / 50 slots used.

#patch

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

include/param_prj.h

@@ -47,7 +47,7 @@
    3. Display values
  */
 //Next param id (increase when adding new parameter!): 24
-//Next value Id: 2052
+//Next value Id: 2053
 /*              category     name         unit       min     max     default id */
 #define PARAM_LIST \
     PARAM_ENTRY(CAT_CHARGER, idclim,      "A",       0,      45,     45,     3   ) \
@@ -109,6 +109,7 @@
     VALUE_ENTRY(c3udc,       "V",     2035 ) \
     VALUE_ENTRY(c3idc,       "A",     2036 ) \
     VALUE_ENTRY(tmpobcmax,   "°C",    2051 ) \
+    VALUE_ENTRY(vcustop,     OFFON,   2052 ) \
     VALUE_ENTRY(test_time,   "s",     3000 ) \
     VALUE_ENTRY(test_timer_flag,   "X",     3001 ) \
     VALUE_ENTRY(test_timer_icvalue,   "X",     3002 ) \
@@ -139,12 +140,18 @@
 // -S9 restores 8 c2/c3 RX entries (uac/flag/idc/udc per module). -S8 over-
 // trimmed multi-module Tesla OBC support: CalcTotals was summing only
 // module 1's contribution, so reported pack power was 1/3 of actual delivery.
-// -S10 adds udclim RX on 0x212 bytes 1-2. With this, the VCU can force a
-// hard stop by sending udclim=200V (below pack), which fires the existing
-// ChargerStateMachine CheckVoltage() exit (udc > udclim → STOP). Closes the
-// gap where Fix B's contactor-open left the OBC modules drawing ~0.55 kW AC
-// indefinitely because EVSEACTIVATE had no other exit path.
-#define VERSTR STRINGIFY(4=VER-S10)
+// -S10 added udclim RX on 0x212 bytes 1-2. The VCU sent udclim=200V to force
+// CheckVoltage() to fire (udc > udclim → STOP). DEPRECATED in -S11: the
+// per-module DC voltage readings (c1udc/c2udc/c3udc) collapse below 200V
+// once VCU opens HV contactors, so the trigger never accumulates 10 ticks.
+// udclim RX is kept mapped but the VCU now always sends 398V (no-op).
+//
+// -S11 adds vcustop RX on 0x212 byte 3 — an explicit VCU command lever that
+// mirrors the Dilong path's OBC_ControlCMD. When VCU enters CHARGE_COMPLETE
+// it sets vcustop=1; ChargerStateMachine's EVSEACTIVATE case transitions to
+// STOP immediately, the J1772 CP signal drops, EVSE stops delivering AC,
+// VCU_IsCharging() returns 0, water pumps power down naturally.
+#define VERSTR STRINGIFY(4=VER-S11)
 
 /***** enums ******/
 

src/charger.cpp

@@ -353,15 +353,28 @@ void ChargerStateMachine()
          DigIo::evseact_out.Set();
          DigIo::acpres_out.Set();
 
-         if (CheckVoltage() || CheckTimeout())
+         // SKUDAK-S11: explicit VCU stop command takes priority over every
+         // other exit condition. When the VCU's BMS-side gate determines the
+         // charge session is complete (or the user lowered ChargeLimit below
+         // current SOC), it sets vcustop=1 on 0x212 byte 3. We obey
+         // immediately — drop AC pres + EVSE-active GPIOs and transition to
+         // STOP. Mirrors how the Dilong path's OBC_ControlCMD = Stopped works.
+         // Replaces the brittle udclim=200V mechanism from -S10.
+         if (Param::GetInt(Param::vcustop))
+         {
+            DigIo::acpres_out.Clear();
+            DigIo::evseact_out.Clear();
             state = STOP;
-         if (CheckUnplugged())
+         }
+         else if (CheckVoltage() || CheckTimeout())
+            state = STOP;
+         else if (CheckUnplugged())
          {
             DigIo::acpres_out.Clear();
             DigIo::evseact_out.Clear();
             state = OFF;
          }
-         if (CheckChargerFaults())
+         else if (CheckChargerFaults())
          {
             DigIo::acpres_out.Clear();
             state = OFF;

src/chargercan.cpp

@@ -100,24 +100,28 @@ void ChargerCAN::MapMessages(CanMap* can)
    can->AddSend(Param::aclim, 0x44c, 16, 16, 1500);
    can->AddSend(Param::opmode, 0x44c, 32, 8, 154, 100);
 
-   /***** SKUDAK VCU command RX (0x212) — SKUDAK-516 user ChargeLimit + S10 stop *****/
+   /***** SKUDAK VCU command RX (0x212) — SKUDAK-516 chglim + S10 udclim + S11 stop *****/
    // Byte 0:    ChargeLimit_pct (0-100). Param::Change(vcuchglim) translates
    //            % to udcspnt setpoint (see src/main.cpp).
-   // Bytes 1-2: udclim_V (uint16 LE, 50-420 V). SKUDAK-S10: VCU drives this
-   //            dynamically so it can force-stop the OBC modules when its
-   //            BMS-side SOC gate trips. Normally 398 V (= default udclim, no
-   //            effect). On the VCU's CHARGE_COMPLETE state it drops to 200 V,
-   //            which fires the existing ChargerStateMachine CheckVoltage()
-   //            path (udc > udclim → STOP within 1 s). Pre-S10 firmware
-   //            ignored these bytes; safe upgrade. NOTE: udclim updates here
-   //            are RAM-only — `save` command WHILE the VCU is forcing 200
-   //            would persist that value and brick subsequent charging. Don't
-   //            issue `save` mid-stop.
-   // Bytes 3-7: reserved 0x00.
+   // Bytes 1-2: udclim_V (uint16 LE). DEPRECATED in -S11 but mapping kept for
+   //            backward compat with -S10 VCU TX. New VCU always sends 398V
+   //            (= the flash default), so this RX is a no-op. Old -S10 trick
+   //            (VCU sends 200V to force CheckVoltage() STOP) was unreliable
+   //            because c1udc/c2udc/c3udc collapse < 200V once VCU opens HV
+   //            contactors, never accumulating 10 ticks > udclim. Defensive
+   //            clamp in Param::Change(udclim) ignores values < 50 V (would
+   //            otherwise turn an old-VCU bench into a never-charges brick).
+   // Byte 3:    vcustop (uint8, NEW in -S11). 0 = no override / normal state
+   //            machine. 1 = VCU commands STOP. Checked at the top of
+   //            EVSEACTIVATE in ChargerStateMachine; transition to STOP fires
+   //            within one 100 ms tick. Mirrors how the Dilong path uses
+   //            OBC_ControlCMD = Stopped to authoritatively halt charging.
+   // Bytes 4-7: reserved 0x00.
    // VCU broadcasts every 200 ms once teslacharger detected; charger holds
-   // last received values if VCU goes silent (held udclim defaults to 398 V).
-   can->AddRecv(Param::vcuchglim, 0x212, 0, 8, 1);
-   can->AddRecv(Param::udclim,    0x212, 8, 16, 1);
+   // last received values if VCU goes silent.
+   can->AddRecv(Param::vcuchglim, 0x212, 0,  8,  1);
+   can->AddRecv(Param::udclim,    0x212, 8,  16, 1);
+   can->AddRecv(Param::vcustop,   0x212, 24, 8,  1);
 
    /***** SKUDAK VCU telemetry (0x211) — SKUDAK-448 expanded charger telemetry *****/
    // Byte 0:    state     (0=Off, 1=WaitStart, 2=Enable, 3=Activate, 4=Run, 5=Stop)

src/main.cpp

@@ -161,6 +161,18 @@ void Param::Change(Param::PARAM_NUM paramNum)
          spnt = MIN(Param::Get(Param::idcspnt), Param::Get(Param::idclim));
          dcCurController.SetRef(spnt);
          break;
+      case Param::udclim:
+         // SKUDAK-S11: defensive clamp. udclim is now reverse-mapped from CAN
+         // (chargercan.cpp), and a pre-PR47 VCU sends 0 in 0x212 bytes 1-2.
+         // udclim=0 would make CheckVoltage() fire on every tick (udc > 0)
+         // and prevent any charging. If we see a value below the documented
+         // min (50V), restore the safe default. Trivial cost — fires only on
+         // CAN RX of udclim (200 ms cadence) and only ever does work when
+         // the value is bogus.
+         if (Param::GetInt(Param::udclim) < 50) {
+            Param::SetInt(Param::udclim, 398);
+         }
+         break;
       case Param::vcuchglim:
       {
          // SKUDAK-516: VCU sends user-set ChargeLimit_pct on CAN 0x212. Translate